Review on Soil Desiccation Cracking Behavior and the Mechanism Related to Fracture Mechanics(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2018年第02期
- Page:
- 223-236
- Research Field:
- 工程地质
- Publishing date:
Info
- Title:
- Review on Soil Desiccation Cracking Behavior and the Mechanism Related to Fracture Mechanics
- Author(s):
- XU Qi-liang; TANG Chao-sheng; LIU Chang-li; ZENG Hao; LIN Luan; HU Zeng-hui
- 1. School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China; 2. Ningbo Rail Transit Group Company Limited, Ningbo 315010, Zhejiang, China
- Keywords:
- soil shrinkage; cracking; development process; mechanical mechanism; fracture mechanics; fracture toughness; stress intensity factor
- PACS:
- P642.11+6
- DOI:
- -
- Abstract:
- Soil shrinkage cracking, which is a common natural phenomenon, can greatly weaken the engineering properties of soil and is a direct inducement for many geotechnical, water conservancy and geological engineering problems. However, at present, there is a lack of in-depth understanding of the mechanism of shrinkage crack development, especially the mechanism of cracking. Based on the research carried out around soil shrinkage cracking in recent years at home and abroad, the application of cracking development mechanism and fracture mechanics theory in this subject were systematically summarized; the research focus and direction of this subject based on the shortcomings of the current research were put forward. The results show that ①evaporation is the premise of soil shrinkage cracking; for the initially saturated soil, the soil is still at saturation stage when the soil cracking occurs, and the water evaporation is at a constant velocity stage; at this moment, the corresponding water content is the critical; ②the soil shrinkage cracking is the result of internal stress; during the drying process, the soil cracks when the tensile stress caused by the matrix suction reaches or exceeds the tensile strength; therefore, the matrix suction and tensile strength are the two key mechanical parameters affecting soil cracking; ③the soil cracking is closely related to the volume shrinkage; shrinkage is the macroscopic manifestation of the movement of soil particles under tension; shrinkage can be divided into three stages (normal, residual and zero shrinkages), and most fractures occur in the normal shrinkage stage, and a small part occurs in the residual shrinkage stage; volume shrinkage provides the space for cracking, so shrinkage is a necessary condition for fracture formation and development; ④fracture mechanics is one of the main tools to study the destruction of soil cracking; there are two ways (stress and energy) to explain the process of fracture development by using fracture mechanics; the involved fracture mechanics parameters are stress intensity factor, fracture toughness and energy release rate; there are all strong evidences for judging whether the soil cracks and when cracks; ⑤the main methods to measure soil fracture parameters are threepoint bend fracture test and direct tensile test, as well as the two improved tests.
Last Update: 2018-04-19